The present invention relates to a steering column assembly which is axially retractable in the event of impact, in particular for an automobile vehicle.
The safety of the passengers and in particular of the driver of an automobile vehicle is a constant concern of equipment suppliers and vehicle constructors.
In order to reduce the risks of injury of these passengers in the event of impact there has been developed in the prior art a number of systems for protecting them.
Thus for example more or less perfected safety belt systems have been developed to maintain the passengers of a vehicle on their seat in the event of impact.
Modules comprising an inflatable bag have also been proposed which are for example integrated in the central bearing of the vehicle steering wheel and in the dashboard on the side of the front passenger.
It will in particular be realized that the steering wheel may become extremely dangerous for the driver of a vehicle in the event of impact.
Indeed, the head of the driver frequently strikes against the steering wheel in the event of an impact and it also occurs, in the event of a large impact from the front, that the steering column assembly carrying this steering wheel is displaced inwardly of the compartment of the vehicle toward the driver, which still further increases the risk of injury to the latter.
In order to overcome these problems, there have therefore been developed in the prior art steering column assemblies which are axially retractable in the event of impact and comprise a support structure fixed to the rest of the vehicle and on which are fixed the ends of a column body in which a steering shaft is disposed.
These column assemblies further comprise means for axially retracting the column body, and consequently the steering shaft, in the event of impact so as to cause the retraction of this body into the dashboard of the vehicle and consequently move the steering wheel away from the driver of the vehicle in the event of impact.
In the prior art, the retracting means for example comprise one or more traction cables associated with direction changing means, one of the ends of the or each cable being connected to the engine of the vehicle and the other to the column assembly for the purpose of retracting the latter in accordance with the rearward displacement of the engine upon impact.
However, these arrangements have a number of drawbacks, in particular regarding their extremely complex and space-consuming structure, their cost and their reliability.